Many vehicle inspection and vehicle analysis procedures require placement of drive wheels of the vehicle on a dynamometer. A dynamometer is a structure which allows the drive wheels of the vehicle to rotate while the vehicle remains stationary. Dynamometers can be fitted with various different sensors, such as sensors to measure the power which is being outputted by the drive wheels of the vehicle. When a vehicle service bay is to be fitted with a dynamometer, it is preferably that the dynamometer be located at least partially below a surface of cementitious material forming the floor of the service bay. Hence, a pit extending below the surface of the cementitious material is required. The dynamometer can then be installed within the pit in a manner which allows a vehicle to be driven off of the floor and onto the dynamometer without requiring that the vehicle ride up a ramp or otherwise perform a complex maneuver.
The cementitious material which is used to form a floor of a vehicle service bay or similar surface typically is formed from appropriate initial concrete materials, combined with water, and then poured in place before being allowed to harden into the desired final shape. The initial concrete materials typically include portland cement, sand, aggregate, lime and water. When this concrete material is in liquid form it can be easily poured into forms which remain in place until the materials harden. The forms are then removed and the desired finished contour for the cementitious material remains.
Hence, when a pit is to be formed in a floor of a vehicle service bay, an area is initially excavated surrounding the location where the pit is desired. Forms are then put in place where the pit is desired to prevent the concrete or other initial cementitious material from filling up the pit when poured. Before the concrete is poured, it is desirable that steel reinforcing bar, called "rebar," be oriented strategically below the surface for the cementitious material and surrounding the pit region. The rebar significantly enhances the strength of the cementitious material and allows the cementitious material to more effectively support the weight of vehicle wheels in the area surrounding the dynamometer pit. Once the rebar is in place, the concrete or other cementitious material is poured up to the desired level for the surface. The cementitious material is then allowed to harden by evaporation of the water from the cementitious material. Finally, the forms are removed so that the pit remains.
While this process of forming a pit within a surface of cementitious material is generally effective, it suffers from a variety of drawbacks. The process of properly orienting the rebar and positioning the temporary forms in place to form the pit can be particularly time consuming. If the forms are not properly spaced relative to the rebar, the strength of the cementitious material is degraded. Also, the forms cannot be removed until the cementitious material is hardened. Hence, installers of the pit, utilizing the prior art techniques, must make at least two trips to the construction site, including one trip to set up the rebar and forms and pour the concrete, and then a second trip after the cementitious material has properly hardened to remove the forms.
Also, the surfaces of the pit are formed by cementitious material adjacent the forms. While cementitious material exhibits sufficient strength characteristics in compression, it is susceptible to cracking and failure in tension loads. Hence, the cementitious material is necessarily not the most desirable material for forming walls of the pit in which the dynamometer is located. Accordingly, a need exists to provide a pit assembly which can be utilized as a form during pouring of the cementitious material but which can remain within the cementitious material and form a lining for the dynamometer pit or other related pit, after the cementitious material has hardened, such that no removal of any portion of the pit assembly is necessary after hardening.